Alexander Pogrebnjak is a Professor at the Nanoelectronics Department Chair at Sumy State University, Ukraine. His scientific interests are related to nanocomposite and layered coatings, high-entropy alloy nitrides, improving physical–mechanical and chemical properties of materials using nanosized films, and modification of properties of metals and alloys by high-power particle beams. Prof. Pogrebnjak has been a Visiting Scientist at Helsinki Technology University (Finland), Trento University (, Italy), Los Alamos National Laboratory and Sandia National Laboratories (USA), the National Institute for Materials Science (Tsukuba, Japan), Lublin University of Technology (Poland), and the University of Poitiers (France). He has co-authored 14 book chapters and over 315 peer-reviewed scientific articles. Dr. Oleksandr Bondar is a Leading Researcher of the Department of Nanoelectronics at Sumy State University, Ukraine. His scientific interests are related to nanostructured and nanocomposite multilayer coatings based on nitrides, carbides of transition and refractory metals, and surface treatment of materials using high-temperature annealing or high-dose ion implantation to improve the protective properties of the coatings. Dr. Bondar has been a Visiting Scientist at the University of Poitiers (France), Adam Mickiewicz University (Poznan, Poland), the National Institute for Materials Science (Tsukuba, Japan), and Riga Technical University (Latvia). He has co-authored 2 patents, 5 book chapters and over 60 peer-reviewed scientific articles.